For suppressing global warming and preparing for depletion of oil resources, an electric vehicle (EV) that travels by electric energy is introduced. In addition, also in a public transportation system such as a route bus, the introduction of the EV progresses. Meanwhile, the EV needs to charge a storage functional unit such as a rechargeable battery that is mounted in the EV. In the case of employing the EV as a route bus, there are a method of charging a storage functional unit once a day so that the route bus can travel for one day, a method of charging a storage functional unit by a charger provided at a terminal or a station, when the route bus stops at the terminal or the station, and the like.
According to the method of charging a storage functional unit of a route bus once a day, a size, cost, and weight of the storage functional unit that are required for storing power for the route bus traveling for one day increase. Thus, the method of frequently charging the storage functional unit while the route bus is stopped at a terminal or a station can save the size and the cost of the storage functional unit more. Furthermore, in this method, a travel distance of the route bus per unit power amount becomes longer due to the weight saving of the storage functional unit.
Nevertheless, the method of charging the storage functional unit while the route bus is stopped at a terminal or a station may decrease running efficiency of the route bus if a time required for charging becomes longer.